Road Engineering

enas saleh

5 months ago

Types of Grade Separation

Grade separation is a method developed to avoid the disruption of traffic flow at intersections. Grade separation is adopted at junctions where two or more surface transport axes cross with each other. Different types of grade separation structures, advantages and disadvantages of grade separation are discussed below.


Types of Grade Separation


Grade separation is generally achieved by my means of a vertical level. For example, if two roads are intersecting at one point on a ground level, then grade separation is achieved by raising or lowering the profile of one of the roads with respect to ground level. So, the traffic from both roads will never meet and safety aspect stays intact.


Grade separation can be achieved by two types of intersections and they are :



  1. Overpass

  2. Underpass


 


1. Overpass


When the vertical profile of one highway is raised with the help of embankments and over-bridge arrangement to eliminate intersection with another highway on ground level, then it is said to be overpass.



2. Underpass


Similarly, when the vertical profile of one highway is lowered with respect to ground level in the form of tunnel to avoid intersection with another highway then it is said to be underpas